Transmitting apparatus.



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No. 834,497. PATBNTBD 001230, 190s.

H. SHOBMAKBR.

TRANSMITTING APPARATUS.

APPLICATION FILED IAB. 2,'1906.

? QVENT? M1245@ ATTORNEY UNITED sTATEs PATENT oEEro-E.

HARRY SHOEMAKER, OF JERSEY CITY, NEW JERSEY, ASSIGNOR TO INTERNATIONALTELEGRAPH CONSTRUCTION COMPANY, A COR- PORATION OF NEW YORK.

Specification of Letters Patent.

Patented Oct. 30,' 1906.

Application led January 2, 1906. Serial No. 294,040.

To all whom, it may concern:

Be it lmown that I, HARRY SHOEMAKER, a citizen-of the United States,residing at Jersey City, in the county of Hudson and State of NewJersey, have invented a new and useful Transmitting Apparatus, of whichthe following is a specification.

My invention relates to telegraph transmitting apparatus, and moreparticularly to means for controlling the operators key. i My inventionresides in apparatus for minimizing sparking at keycontacts, especiallywhen the key is required to control an alternating or fluctuatingcurrent and when such current is of considerable magnitude, as in thecase of telegraph systems employing electroradiant energy and commonlyknown as wireless-telegraph systems.

In some telegraph systems, especially wireless-telegraph systems, theoperators key is required to control or interrupt considerable energywith certainty and clearness. Large currents cause danger of destructionof the key-contacts by arcing or sparking. To this end I associate withthe operators key an electromagnet connected either in series with or inshunt to the circuit controlled by the key, such magnet operating toretain the key in closed position until the alternating or fluctuatingcurrent reaches or nearly reaches its minimum value.

For several of the forms my invention may take reference is to be had tothe accompanying drawings, in which- Figure 1 is a side elevationalview, partly in section, of a telegraph-key and an associatedelectromagnet. Fig. 2 is a vertical elevational view, partly in section,taken at right angles to Iig. 1. Fig. 3 is a diagrammatic view of simpletransmitting-circuits involving an electromagnet associated with the keyhaving its Winding in series with the circuit controlled by the key.Fig. 4 is a view similar to Ii ig. 3, except that theelectromagnet-Winding is connected in shunt to the circuit controlled bythe key. Fig. 5 is a fragmentaiy diagrammatic view showing amodification of l* ig. 4.

Referring to Fig. 1, K is an'operators key pivoted at 1 and having theusual finger-button 2. A spring or other means (not shown) serves tokeep the key in open-circuit position, as is well understood andcoInInol; in

telegraphy. The key-contacts are shown at 3 and 4.

5 is an iron armature, preferablylaminated, secured to the under sideand extending transversely ofthe key-bar K.

6 6 are vertically-extending magnet-cores having the common yoke or backarmature 7, the latter resting upon the adj usting-screw 8, passingthrough a member 9, constituting a portion of or a xture to the frame inwhich the bar K is pivoted. Embracing each core 6 is a closed-circuitedwinding or circumferentially-continuous tube 10, of copper or otherwell-conducting material. The tubes 10 10 may terminate in flanges 1 1,which may serve both to radiate any excessive heat that may be generatedin the tubes 10 10 and as a Winding-space for the windings 12 12, whichmay be either series or shunt windings, as hereinafter described.

In Fig. 3, simply by way of example,` a l simple Wireless-telegraphtransmitting apparatus is shown, and applied thereto is my invention. Arepresents a simple aerial conductor, between which and the earthconnection E is a spark-gap g. Bridging the sparkgap is the secondary Sof a step-up transformer whose primary is shown at P. In series with theprimary P is the generator or source of electricity G, preferably analternating-current generator. For long-distance Working considerableenergy must be delivered by the generator G and must be controlled bythe key at its contacts 3 and 4, which are also connected in series withthe rimary P and with the Winding 12 of the e ectromagnet. Theconducting-tubes 10 10 are shown diagrammatically only. When the key Kis depressed by the operator, the current flows through the winding 12and the primary P in series, causing sparks at the gap g and theradiation of electroradiant energy from A` In so depressing the key thearmature 5 has been brought within the range of action of the poles ofthe cores 6 6 and attracted thereby, thus, in effect, assisting theoperator in holding the key down in circuit-closed position.Remembering, however, that the current in the circuit of the key4 is analternating one or a fluctuating one, it may occur, as `it doesrequently in practice, that the operator will remove the pressure fromthe key at an instant of time When the current in the circuit IOO is ator near its maximum, or at any rate at a value considerably greater thanzero. In the absence of the electromagnet, as here shown, the key wouldopen at the instant the operator removed the pressure, with resultantspluttering and arcing at the contacts 3 and 4, due to the fact that atthat instant the current is of considerable magnitude. This arcing and sluttering soon destroys the efficiency of a ey, requiring itsreplacement or at least interfering with the' transmission of clearsharp signals. By the use of the electromagnet, however, the key is heldover an interval of time after the operator may have released pressurewhen the current is at: a considerable value. When the current reachesor approximately reaches its minimum value, howe ver, the strength ofthe magnet is correspdingly reduced and releases the key at t instant ofsmall or zero value, with the rt ult that practically no arcing occursat the contacts 3 and 4. This means that such contacts are not damaged,have a long life, and that the signaling is and continues to be clearand sharp.

l Since the windings 12 12 upon the cores 6 6 are inductive ones inthe-relation shown, the current lags behind the impressed electromotiveforce, as is well understood in the art of alternating currents. Theclosed-circuit.- ed Winding or. circumferentially-continuous tubes 10 10serve as closed secondaries and tend to bring the current andelectromotive force more nearly into phase-that is, they tend to shiftthe phase ofthe magnetism.

In Fig. 4 the arrangement is similar' to that in F ig. 3, except thatthe key, the generator G, and primary P are in series With each other,no electromagnet-winding being series in-this case. However, the-magnet-Winding 12 u on the core 6 is connected in shunt to the circuitcontrolled by the key, so that the key controls the circuit, of themagnet l2 as well as that of the primary P. In this case the number ofturns upon the ma net is greater-than in the case of Fig. 3 and t eselfinductionis also considerably greater. To shift the phase of thecurrent with respect to the electromotive force in the coil 12', thecircumferentially continuous tubes 10 .10 o erate as closed secondaries.The adjustahle or suitable condenser C may be connected in series withthe Winding 12 to bring the current more nearly in phase with theelectromotive force or to otherwise shift the current, hase or the phaseof the magnetism. Either t e condenser C or the tubes 10 10 may be usedseparately and independently or all may be used conjointly.

In Fig. 5 the arrangement is similar to that inF-ig. 4, except that thecondenser C is connected-in shunt to the magnet-windin l2.

Iy the apparatus herein descrlbed the operators key, if not released bythe operator at or near the instant of minimum current in the circuit,is held over by an electromagnet and then released by the magnet at ornear the instant of 'minimum current, with resultant reduction of arcingor sparking, as heretofore described.

By adjusting the screw 8 the electromagnet may be caused to approach orrecede from the armature 5, thus giving an advantageous adjustment forthe control exercised by the electromagnet.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In a telegraph-transmitter, anl operators key, a source ofalternating/or' fluctuating current, an electromagnet operating uponsaid key, the winding of said: magnet being connected in shunt to thecircuit controlled by said key, whereby said key isrpermitted to returnto normal position only at or nearthe instant of minimumcurrent.

2. In a telegraph-transmitter, an operators key, a.I sourceoffluctuating or alternating current controlled by said key, anelectromagnet associated with said key for permitting its return tonormal-position only at or near the instant of minimum current and aiphase-shifting device associated with said electromagnet.

3. In a signaling system, anoperators key, a source of iiuctuatinor-alternating current controlled by said ey, an electromagnetassociated with said key for ermitting its returnto normal position on yat' or near the instant' of minimum current, and a closed-circuitedwinding associated with the Winding of said electromagnet.

4. In asignaling system, an. operators key, a source ofl uctuating oralternating current controlled thereby, anelectromagnet associated withsaid key for permittingits return to normaliposition only at: or nearthe instant of minimum current, anda condenser associated with-thewinding of' said electromagnet. 4

5. In a wireless signaling system, afradiating-conductor, a source offluctuating or alternating current-for supplying energy thereto, anoperators key for controlling said energy, an electromagnet associatedwith said key for permitting its return to normal position only at ornear the instant of minimum current, and a phase-shifting deviceassociated with the winding of said electromagnet.

6. In a wireless signaling system, aradiating-conductor, a source offluctuating or alternating current for supplying energy thereto, anoperators key for controlling said energy, an electromagnet associatedwith said key for permitting lts return to normal position only at ornear the instant of minimum current, and a closed-circuited windingassociated with the winding of said electromagnet.

7. In a wireless signaling system, a radiat.-

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ing-conductor, a source of fluctuating or alternating current forsupplying energy thereto, an operators key for controlling said energy,lan electromagnet associated with said key for permitting its return tonormal position only at or near the instant of minimum current, and acondenser associated with the Winding of said electromagnet.

8. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, anoperators key for controlling said energy, and an electromagnet, havingits Windin connected in shunt to the circuit controlled by said key, forpermitting the return of the key to normal position only at or near theinstant of minimum current.

9. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling said energy, an electromagnet associated with said keyfor holding it closed until at or near the instant of minimum cu'rrent,and a closed circuit associated With the magnetic circuit of saidmagnet.

10. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling said energy, an electromagnet associated with saidsource of energy and key for holding said key closed until at or nearthe instant of minimum current, and a conducting-sleeve associated Withthe magnetic circuit of said magnet.

11. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling said energy, an electromagnet associated with said keyfor holdin it closed until at or near the instant of minimum current anda phase-shifting device associated With a Winding of said magnet.

12. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling lsaid energy, an electromagnet associated with said keyto hold it closed until at or near the instant of minimum current, aWinding of said magnet being connected in shunt to the circuit includingsaid source of energy, and a phase-shifting device associated-With saidWinding.-

13. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling said energy, an electromagnet associated With said keyto hold it closed until at or near the instant of minimum current, aWinding o f said magnet being connected in shunt to the circuit includinsaid source of ener y ary; controlled by saicgl key, and a phase-siftigA g device associated Said '53.5'

14. In a Wireless signaling system, a radiating-conductor, a source offluctuating or alternating current for supplying energy thereto, a keyfor controlling said energy, and an electromagnet associated with saidkey for holding it closed until at or near the instant oi minimumcurrent, a Winding of said magnet being connected in shunt to thecircuit ilpcluding said source and controlled by said 15. In a Wirelesssignaling system, a radiating-conductor, a source of fiuctuating oralternating current for supplying energy thereto, a key for controllingsaid energy, an electromagnet associated With said key to hold it closeduntil at or near the instant of minimum current, a winding of saidmagnet being connected in shunt to the circuit includino said source ofenergy, and a closed circuit and a condenser associated with saidmagnet- Winding.

In testimony affixed my signature in the two subscribing Witnesses.

HARRY SHOEMAKER.

whereof I have hereunto presence of the Witnesses:

ALICE S. MARSH, AGNES Rim).

